Transient infrared emission spectroscopy by pulsed laser excitation

Jones, Roger; McClelland, John F.

doi:10.1021/ac00192a006

Cited by 22 publications

(9 citation statements)

References 35 publications

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“…Recently a new technique called transient infrared emission spectroscopy (TIRES) was introduced that can analyze optically thick samples in motion by reducing self-absorption (2,3). In TIRES a thin surface layer of the sample is rapidly heated and thermal emission from this layer is collected before it thickens and cools by thermal diffusion.…”

Section: Literature Citedmentioning

confidence: 99%

Quantitative analysis of solids in motion by transient infrared emission spectroscopy using hot-gas jet excitation

Jones¹,

McClelland²

1990

Anal. Chem.

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can be obtained only with less-volatile paraffins, since highvolatile paraffins will vaporize from ultrafine particles within milliseconds due to the Kelvin effect (16). A solution to this problem may be the application of a heated (ca. 323 K) thermodenuder in front of the photoelectric aerosol sensor, which will remove not only high-volatile paraffins but also other interfering products (8). CONCLUSIONSThe presented investigations have shown that an additivity of the photoelectric signals is given only for small PAH coverages on particles. In real exhaust situations similar PAH concentrations exist while the particle concentrations are substantially larger at least by a factor 1000; hence only low PAH surface coverages will result from real combustion processes except for residential wood combustion. Under these circumstances the photoelectric signal is likely to represent the sum of the single signals of all adsorbed PAHs. Analyzing cigarette smoke aerosols with the photoelectric aerosol sensor (A = 185 nm) and parallel wet-chemical techniques have confirmed the strong correlation between photoelectric signal and adsorbed PAH amounts (17). Also the applicability of this sensor as on-line and in situ detector for the measurement of PAHs in exhaust gases from waste combustion has been tested (18). Experiments with paraffin coatings have confirmed that aerosol photoemission only probes the surface composition of an aerosol system. LITERATURE CITEDLevsen, K. Fresenius' J. Anal. Chem. 1988, 333, 467-478. Partrklge, P. A.; Shah, F. J.; Cernansky, N. P.; Suffet, I. H. Envhon. Sci. Techno/. 1987, 27, 403-408. Davis, C. S.; Fellin, P.; Otson, R. Quantitative compositlonal analysis of optically tMck SOW In motlon Is demonstrated by urbrg trandent Infrared emlsslon spectroocopy (TIRES). TIRES greatiy reduces the self-absorptkn that nonndly degrades comrenUona1 emlsskn spectra so that they dosdy resembb Msckbody spectra. Quantltathre composltlonal analyses of poly[( methyl methacrylate)-co -(butyl methacrylate)] and poly[ethylenaco-(vlnyl acetate)] with standard errors of predlctlon under 1 % were achleved with only a few seconds of data acqulsition uslng prlnclpal compomtt regresgkn. Use of a hotgas j e t in place of a laser In the TIRES technique allows study of materials that do not absorb strongly at common laser wavelengths whlle reducing cost and complexlty.

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Section: Literature Citedmentioning

confidence: 99%

Quantitative analysis of solids in motion by transient infrared emission spectroscopy using hot-gas jet excitation

Jones¹,

McClelland²

1990

Anal. Chem.

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“…17 However, the low sensitivity of the diffraction grating instrument and the low spectral resolution (Dl/l ø 0.1) of the interference lters limits their range of applications. Jones and M cClelland rst exploited the multiplex advantage of an FT-IR interferometer to measure high-resolution transient thermal emission and transmission spectra using a variety of excitation sources (pulsed and sinusoidally modulated lasers, 18,19 hot and cold air jets 20,21 (a) semi-in nite homogeneous sample, (b) two-layer samp le with optically thin top layer, and (c) two-layer sample with optically thick top layer.…”

Section: Introductionmentioning

confidence: 99%

Spectral Depth Profiling of Arbitrary Surfaces by Thermal Emission Decay—Fourier Transform Infrared Spectroscopy

et al. 2003

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We report a new spectroscopic technique that combines step-scanning Fourier transform infrared spectroscopy with opto-thermal transient emission radiometry (OTTER) in order to provide near-surface depth-resolved spectra in the range 700–1800 cm−1. It works nondestructively, without contact, with samples of arbitrary shape and size, without requiring prior preparation. The depth of surface probed depends on the thermal diffusivity of the sample; for organic materials it is ∼10 μm. With homogeneous samples, absolute absorption coefficients can be measured. With two-layered samples, the technique proved able to distinguish between the spectral properties of the top layer and the substrate and to estimate the thickness of the top layer. We present a theoretical analysis with the main design features of the instrumentation and software, together with studies of homogeneous and layered samples, to validate the methods and illustrate the potential of the technique for practical applications.

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“…Recently a new method called transient infrared emission spectroscopy (TIRES), which can analyze in real time optically thick solids in motion, has been under development (5)(6)(7). In TIRES an optically thin surface layer of the sample is rapidly heated for an instant and thermal emission from this layer is collected before it thickens and cools by thermal diffusion.…”

Section: Introductionmentioning

confidence: 99%

“…Many experimental parameters affect TIRTS the same way that they do TIRES. For example, the amount of saturation (caused by self-absorption) in TIRES spectra is largely controlled by how long the emission is observed after the surface layer is heated (5,6). TIRTS has a similar dependence because the chilled surface layer starts to thicken immediately after being formed.…”

Section: Introductionmentioning

confidence: 99%

“…IO waveguides, particularly those fabricated from thin, transparent polymer films of micron dimensions, have attracted considerable interest as a means of acquiring Raman spectra from monolayers deposited on the waveguide surface or of the waveguide material itself (5)(6)(7)(8)(9). In spite of the low efficiency of Raman scattering, IO waveguide Raman spectroscopy is a feasible experiment due to (1) the extremely high optical field intensities that can be generated in the guide and (2) the increased path length created by the large number of internal reflections per centimeter.…”

Section: Introductionmentioning

confidence: 99%

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Transient infrared transmission spectroscopy

Jones¹,

McClelland²

1990

Anal. Chem.

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Transient infrared transmission spectroscopy is a new method that can acquire analytically useful transmission spectra from moving, optically thick solids. No sample preparation is required. The spectra are of sufficient quality for accurate quantitative compositional analysis. The method works by the creation of a thin, short-lived, chilled layer at the sample surface. Blackbody-like thermal emission from the bulk of the sample is selectively absorbed as it passes through the chilled layer, so the transmission spectrum of the layer is superimposed on the observed thermal emission. Spectra of polycarbonate, beeswax, and copolymers of methyl and butyl methacrylate are presented. Compositional analysis of the methacrylate copolymers with a standard error of prediction of only 0.87 mol % is demonstrated.

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Transient infrared emission spectroscopy by pulsed laser excitation

Cited by 22 publications

References 35 publications

Quantitative analysis of solids in motion by transient infrared emission spectroscopy using hot-gas jet excitation

Quantitative analysis of solids in motion by transient infrared emission spectroscopy using hot-gas jet excitation

Spectral Depth Profiling of Arbitrary Surfaces by Thermal Emission Decay—Fourier Transform Infrared Spectroscopy

Transient infrared transmission spectroscopy

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